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When to Plant Fava Beans in Lake County, CO

Fava beans are a cool-season legume with large, meaty beans inside thick pods. They fix nitrogen in the soil and are one of the oldest cultivated crops.

Lake County, Colorado is in USDA Zone 4a. The average last spring frost is June 21 and the first fall frost is August 30, giving you a growing season of approximately 70 days.

At an elevation of 7,687 feet, Lake County receives approximately 21.2 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Fava Beans to ensure they mature before fall.

Lake County, CO (Zone 4a) Very short season
70 days
Last Spring Frost June 21
70 growing days
First Fall Frost August 30

Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 5 Transplant: Jun 16 🍅 Harvest: Sep 1 – Oct 13
Recommended (50%) ✗ May not fit
Start indoors: May 10 Transplant: Jun 21 🍅 Harvest: Sep 6 – Oct 18
Safe Start (90%) ✗ May not fit
Start indoors: May 16 Transplant: Jun 27 🍅 Harvest: Sep 12 – Oct 24

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Fava Beans needs ~1,072 GDD — county provides 857 GDD May not mature

Fava Beans Planting Timeline โ€” Lake County, CO

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors May 10 May 10 โ€“ May 24
Transplant Outdoors June 21 Jun 21 โ€“ Jul 5
Direct Sow June 14 Jun 14 โ€“ Jul 5
Fall Sowing June 7 Jun 7 โ€“ Jun 21
Harvest September 6 Sep 6 โ€“ Oct 18

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
July Transplant Outdoors Direct Sow
August โ€”
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

75โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

70 days

Growing Tips for Lake County

Direct sow as early as soil can be worked in spring. Pinch growing tips when pods begin to form to redirect energy and reduce aphid problems. Stake tall varieties.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Level Up Your Garden

Frequently Asked Questions

When should I plant Fava Beans in Lake County, CO?

Lake County is in Zone 4a with an average last frost of June 21. Plan your Fava Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lake County, CO?

Lake County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 21 and first fall frost is August 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lake County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lake County, CO. Local conditions may vary. Last updated: April 2026.